Ex-Officer Joseph Walsh (left), former Detective David March (middle) and Chicago Police Officer Thomas Gaffney (right) arrive in court on the first day of their trial with Judge Domenica A. Stephenson at Leighton Criminal Court Building in Chicago on Tuesday, Nov. 27, 2018. Officer Thomas Gaffney, former officer The three are accused of conspiracy, obstruction of justice, and official misconduct for allegedly filing false reports to protect their colleague, officer Jason Van Dyke, in the controversial shooting death of Laquan McDonald.(Photo: Zbigniew Bzdak, AP)

CHICAGO – Prosecutors said Thursday that three Chicago police officers accused of conspiring to cover up the controversial shooting death of 17-year-old Laquan McDonald failed to abide by the cardinal rule of policing: Obey the law.

Defense attorneys pushed back, saying the officers did their level best to report on what they witnessed in the October 2014 confrontation, and had become victims of an overzealous prosecution driven by a hyper-politicized, anti-police climate in the nation's third-largest city.

The sides made their closing arguments Thursday in the trial of Officer Thomas Gaffney, former Officer Joseph Walsh and former Detective David March for conspiracy, obstruction of justice and official misconduct.

The officers opted for a bench trial. That means their fate will be decided by Cook County Associate Judge Domenica Stephenson, not a jury. She said she will issue her verdict on Dec. 19.

Van Dyke, who shot the black teen 16 times, was found guilty in October by a Chicago jury of second-degree murder and 16 counts of aggravated battery. He awaits sentencing.

“Obey the law,” special prosecutor Patricia Brown Holmes said in her closing statement Thursday. “That’s what police officers learn through their rules and regulations. Don’t do things you arrest people for doing: Lying, cheating, falsifying, violating the law.”

James McKay, an attorney for March, countered that "following the law was a foreign concept to Laquan McDonald" on the night of the encounter.

“Thank God, we're in a courtroom,” McKay said. “A courtroom where evidence matters. Not outside noise. Not misinformation. Evidence matters here. Not labels, promoted by people that weren’t there.”

In this Oct. 20, 2014 frame from dashcam video provided by the Chicago Police Department, Laquan McDonald, right, walks down the street moments before being fatally shot by officer Jason Van Dyke sixteen times in Chicago.(Photo: AP)

Van Dyke was the only officer to open fire on McDonald. But prosecutors say Gaffney, March and Walsh provided or signed off on inaccurate reports that the teen lunged at Van Dyke with a knife and described officers as victims of an assault by McDonald.

Police dashcam video of the incident shows McDonald veering away from Van Dyke when he opened fire, and witness testimony also contradicted the officers’ description, prosecutors say.

The shooting of McDonald, a troubled teen who had been in and out of the juvenile justice system, widened the chasm between police and Chicago's African-American residents. It's one of several deadly confrontations nationwide that has sparked a broader conversation about policing in black communities.

City leaders resisted releasing footage of the shooting until they were ordered by a court to do so. Its release more than a year after the shooting spurred protests.

Activists say an unofficial “code of silence” persists in the nation’s largest police department, allowing bad cops to act with impunity.

Mayor Rahm Emanuel said a “code of silence” had tarnished the department’s reputation and created a chasm between officers and the community.

Emanuel introduced a series of police reforms in the aftermath of the shooting. Still, he saw his standing in the city's African-American community plummet. He announced in September that he wouldn’t seek re-election.

Attorneys for the officers said there was no conspiracy. At worst, they said, the men made minor errors in writing their reports. They said the prosecutors failed to show the officers collaborated, and claimed the prosecution was politically motivated.

McKay called the prosecution’s case “ridiculous” and witness testimony “a crock.” If March had wanted to cover for Van Dyke, he argued at one point during the trial, he would have tossed the video of the shooting “in the middle of Lake Michigan.”

Gaffney and his partner were among the first to respond to reports of a person breaking into vehicles in a truck lot on Chicago's Southwest Side. They said they encountered McDonald wielding the knife.

Authorities say McDonald had PCP in his system. He ignored repeated calls from police to drop the knife. Officers followed him for several blocks. At one point, he popped the tire of a police and scratched the windshield of Gaffney’s squad car.

Van Dyke and Walsh, partners on the night of the shooting, arrived together in a squad car. Van Dyke jumped out and within seconds opened fire.

Van Dyke told investigators that McDonald raised the knife in a menacing manner, and that he backpedaled as the teen approached. The police video does not support his account.

Walsh said he, too, "backed up" as McDonald got to within 12 to 15 feet of the officers, according to police documents. He said the teen "swung the knife toward the officers in an aggressive manner."

His attorneys maintained “it is demonstrably true that there were three officers that were victims of assault that night."

Attorney Thomas Breen said that identical accounts from the officers reflected "consensus, not conspiracy."

"Maybe you think he’s wrong in how he filled out (the forms)," Breen said. "But that doesn’t make him a criminal."

Gaffney, who requested that officers equipped with a taser come to the scene, indicated in an official post-incident report that Van Dyke and other officers were battered in the incident. No officers were hurt.

Holmes argued Gaffney should not have completed a form known as a tactical response report describing the officers as victims.

She noted that his partner, Joseph McElligott, testified in the Van Dyke trial that McDonald never made "any direct movement at me."

Still, Holmes said, Gaffney listed McElligott in his report as being assaulted by McDonald.

“He did so he could lend his voice to the choir that was singing for the justification of the killing of Laquan McDonald,” she said.

William Fahy, Gaffney’s defense attorney, said the officer might have made minor mistakes in his reporting, but the prosecution’s theory that the paperwork demonstrated an attempt to cover up the shooting “simply doesn’t make sense.”

Fahy said Gaffney did not witness the shooting, and his report was referring to McDonald popping the tire and scratching the windshield of his squad car.

"Judge, a mistake is not a crime," Fahy said. "And disagreeing with a police report, doesn’t make a report writer a criminal."

March, the lead detective, allegedly signed off on statements given by officers at the scene and indicated that there was no discrepancy between what the officers said happened and police dashcam video.

Earl Briggs, an investigator for the Cook County Medical Examiner’s Officer, testified that March told him in a telephone conversation that McDonald lunged at Van Dyke before being shot. Briggs used that information to fill out a report for his office. He said he read the account back to March.

Chicago police Officer Dora Fontaine testified that March directed her to write that Van Dyke was injured by McDonald and attributed false statements to her in his reports.

McKay countered that it was unfathomable that March, who had not met Fontaine before the night of the McDonald shooting, would have enlisted her in a conspiracy.

Fontaine, who received immunity from prosecutors for her testimony, said she has been shunned by colleagues as a ‘rat, a snitch, a traitor."

Defense attorneys and Chicago’s Fraternal Order of Police, which paid for Fontaine’s legal counsel, painted her as lacking credibility.

"She has 90,000 reasons to lie, plus some benefits," said McKay, a reference to her salary.

Gaffney, March and Walsh declined to testify. Defense attorneys called a single witness, retired Detective Nancy Piekarski-Block. She testified that she was tasked with entering reports into the department's database, and that March did not have access to alter them after they were entered.

Special assistant prosecutor Ron Safer said the dashcam video disproved claims that officers were in imminent danger. He said the similarity of the officers’ inaccurate statements strongly suggest they collaborated to write false reports.

Walsh, Van Dyke and Gaffney all checked a box on their reports that McDonald committed a battery with a deadly weapon against them, Safer said. They also checked a box that McDonald used force against them that was likely to cause death or great bodily harm.

"This case is (about) what happened after the shooting and with the luxury of time and perspective," Safer said. "This case is not only important to the defendants but to the people. They did abuse the public’s trust. They violated the law. There has to be a consequence for that."

Prosecutors presented a series of emails sent and received by supervisors to suggest there was a broad effort within the department to help Van Dyke justify the shooting. None of the emails were written by the officers on trial.

Sgt. Daniel Gallagher, who was March’s boss, wrote to Lt. Anthony Wojcik weeks after the incident that police officers are “trained to shoot until the threat is eliminated, defeated or neutralized.”

“Officer did exactly what he was trained to do,” Gallagher wrote of Van Dyke. “We should be applauding him, not second-guessing him.”

In an April 2015 email, Ron Hosko, president of the Law Enforcement Legal Defense Fund, asked Wojcik, “Tony, any luck making the case go away?”